#include <stdio.h>
#include <math.h>
struct hen{
	double a;
	double b;
	double c;
}length;
int main(void) {
	// your code goes here
	double S,s;
	scanf("%lf",&length.a);
	scanf("%lf",&length.b);
	scanf("%lf",&length.c);
	
	s=(length.a+length.b+length.c)/2;
	printf("%lf\n",s);
	S=s*(s-length.a)*(s-length.b)*(s-length.c);
	
	printf("%lf",sqrt(S));
	return 0;
}